- Recent study states that cells of blood ’older’ than 5 weeks can become damaged.
- Transfusion of old blood, which is 6 weeks old, causes impaired metabolization of the damaged cells in the person receiving the blood.
- This causes the release of large amounts of iron into the bloodstream of the recipient which increases risk of blood clots and infections.
The oldest blood available for transfusions releases large and potentially harmful amounts of iron into patients' bloodstreams.
The new study was conducted by researchers at Columbia University Medical Center (CUMC).
Transfusion of red blood cells is the most common procedure performed in hospitalized patients, with approximately 5 million patients receiving red blood cell transfusions annually in the United States.
In the U.S, every two seconds someone needs blood.
About 36,000 units of red blood cells are needed every day in the U.S. The average red blood cell transfusion each year is approximately 3 pints.
Sickle cell anemia affects 90,000 to 100,000 people in the U.S. Around 1,000 babies are born with the disease each year. Sickle cell patients require frequent blood transfusions throughout their lives.
In 2016, more than 1.68 million people are expected to be diagnosed with cancer and most of them will need blood during their chemotherapy treatment.
A single car accident victim may need about 100 pints of blood.
Currently the U.S. FDA allows units of red blood cells to be stored for up to 6 weeks before they must be discarded.
But based on their recent findings, researchers recommend that the FDA reduce the maximum storage limit of red blood cells from 6 weeks to 5 weeks, as long as there are sufficient blood supplies available.
"Our recommendation will be controversial, but we think we have real data to support it," said the study's co-leader Steven Spitalnik, MD, professor of pathology & cell biology at CUMC and medical director of the clinical laboratories at NewYork-Presbyterian/Columbia.
"Recent studies have concluded that transfusing old blood has no impact on patient outcomes, but those studies didn't exclusively examine the oldest blood available for transfusions. Our new study found a real problem when transfusing blood that's older than 5 weeks." Spitalnik added.
"But the longer you store blood, the more the cells become damaged," said the study's co-leader Eldad Hod, MD, associate professor of pathology & cell biology at CUMC and clinical pathologist at NewYork-Presbyterian/Columbia.
Investigating Effects of Old Blood
A group of 60 healthy volunteers were randomly assigned to receive a unit of red blood cells that had been stored for 1, 2, 3, 4, 5, or 6 weeks.
The volunteers were then monitored for 20 hours after transfusion.
Within hours after transfusion, 7 of the 9 volunteers who received the 6-week-old blood could not appropriately metabolize the damaged cells, thereby releasing large amounts of iron into their bloodstream.
Only one volunteer who received 'younger' blood that had been stored for 5 weeks had a similar response.
Previous studies have shown that excess iron can promote blood clot formation and increase risk of infections.
But none of the volunteers were harmed by the transfusion.
"Based on the amount of iron circulating in the blood of the volunteers who received 6-week-old blood, we'd predict that certain existing infections could be exacerbated," said Dr. Hod.
"Thus, for ill, hospitalized patients, this excess iron could lead to serious complications," said Dr. Spitalnik says.
Though the true impact of 6-week-old blood on the rate of complications in patients is likely to be small, even a 1% difference in complications could affect a large number of patients since millions of Americans receive transfusions each year.
"It's estimated that up to 10 to 20 percent of blood units used for transfusions have been stored for more than 5 weeks, so the number of patients who are likely to receive a unit of very old blood is substantial," Dr. Hod added.
"Based on our findings of potential harm, we think the prudent thing to do at this time is for the FDA to reduce the maximum storage period," said Dr. Spitalnik.
The U.K., Ireland, the Netherlands, and the National Institutes of Health have limited storage to 35 days, and this can be achieved throughout the U.S. without seriously affecting the blood supply.
Their findings appear in the Journal of Clinical Investigation.
- Blood Facts and Statistics - (http://www.redcrossblood.org/learn-about-blood/blood-facts-and-statistics)
- Steven Spitalnik. Prolonged red cell storage before transfusion increases extravascular hemolysis. Journal of Clinical Investigation; (2017) doi:10.1172/JCI90837